Say, for example, I have only one RCA connection, but I have 4 or 5 speakers.
I want to hook them all up, for something like surround sound. I do, however, have a lot of speaker wire.My plan is to just plug in speaker #1 to the RCA connections, then run a speaker wire from speaker #1 to speaker #2 etc…
About 20 years ago, I heard that hooking them up in a series, rather than having their own direct to the amp/whatever/RCA connection, would ruin the speakers. I scorned the idea at the time, but, now, I have some great Bose speakers and i don’t want to fry them.
Can I hook the speakers up in a series without damage to them?
Impedance adds in series, and, if equal, divides in parallel.
Two eight ohm speakers in series will be 16 ohms. Two pairs of series speakers, in parallel with two others will give eight ohms.
At some point the amplifier will have trouble sourcing enough current.
It won’t be “true surround sound” if they are all fed by the same amp.
what device would you be connecting them to? an RCA output is usually not powered, so you’d need some kind of amplifier in the chain.
as for the technical part of your question, it depends on how you connect the speakers. If you connect them in parallel, the impedance will probably be too low for the amplifier to tolerate, and at best it’ll go into protect mode, at worst it’ll be damaged.
If you connect them in series, the amplifier should in theory be fine, but sound quality will very likely be worse. adding the impedance of a speaker in line with another speaker raises the total circuit impedance, and the “damping factor” seen by any one speaker in the chain will be shot to hell. I doubt anything would be damaged, though.
Illustrations of speakers in series and parallel.
And I’m assuming the RCA jack(s) is the amp output to speakers. not a line output that needs to see an amplifier.
I recall a circuit with a 4.7 Ohm resistor in series with the load and a 47 Ohm in parallel with it that would provide a matched impedance with any load.
Of course they need to have a huge power rating.
I just did this to power two pairs of 4 ohm speakers from a little amp. I am confident it won’t hurt anything - while hooking them up in parallel could overload the amp.
For a given amp and type of speaker, and referring to just one channel, two speakers in parallel would be about 3 dB louder than a single speaker, and two speakers in series would be about 3 dB quieter.
For the sake of sound quality I think it is important that all the speakers in series should be the same type (the same brand and model number). This is because their real impedance would be a function of frequency, and you want to make sure it’s the same function. Otherwise the distribution of power between the two speakers would be different at different frequencies. This would not be an issue in parallel hookups because the amplifier is making sure the voltage at any given time is correct and letting the speakers dictate the current. Parallel hookups guarantee both speakers get the same voltage, whereas series hookups guarantee both speakers get the same current, and conventionally it is the voltage that the amplifier must make correct.
Any amp that uses RCA jacks for speaker connections is going to be pretty low-powered and I don’t expect it would be able to handle multiple speakers very well.
As Napier mentioned, if you run speakers in series, they really should be identical as a speaker’s impedance will change with frequency, and the sonic outcome will be poor - one speaker may wind up sounding muffled and the other goes the opposite way and sounds tinny or shrill, even though on their own, either speaker sounds good.
